What Is CTE?

Chronic Traumatic Encephalopathy

Chronic Traumatic Encephalopathy (CTE) is a progressive degenerative disease of the brain found in athletes (and others) with a history of repetitive brain trauma. This trauma, which includes multiple concussions, triggers progressive degeneration of the brain tissue, including the build-up of an abnormal protein called tau. These changes in the brain can begin months, years, or even decades after the last concussion or end of active athletic involvement. The brain degeneration is associated with memory loss, confusion, impaired judgment, paranoia, impulse control problems, aggression, depression, and, eventually, progressive dementia.

CTE can only be definitively diagnosed through post-mortem examination of the brain, although efforts are underway to learn how to diagnose CTE in living people, a key step to developing a treatment for the disease.
First called “punch drunk” syndrome and dementia pugilistica, CTE was first described in 1928 by New Jersey pathologist Harrison Martland in “Martland HS: Punch drunk. JAMA 91:1103–1107, 1928” in which he noted symptoms such as slowed movement, tremors, confusion, and speech problems typical of the condition. In 1973, a group led by J.A. Corsellis described the typical neuropathological findings of CTE after post-mortem examinations of the brains of 15 former boxers.

The term “Chronic Traumatic Encephalopathy” appears in the medical literature as early as 1966 and is now the preferred term. Through 2009 there were only 49 cases described in all medical literature since 1928, 39 of whom were boxers. Many thought this was a disease exclusive to boxers, although cases have been identified in a battered wife, an epileptic, two mentally challenged individuals with head-banging behavior, and an Australian circus performer who was also involved in what the medical report authors referred to as “dwarf-throwing.”

CTE was not well known in sports outside of boxing until a Pittsburgh medical examiner named Bennet Omalu identified CTE in two former Pittsburgh Steelers who died in his jurisdiction in 2002 and 2005 and published his findings in two case reports. The work drew the attention of SLI co-founder Chris Nowinski as we was writing Head Games: Football’s Concussion Crisis, and he began reaching out to families of recently deceased former athletes to accelerate the work. He coordinated three more cases in 2006 and 2007 that Dr. Omalu and others diagnosed with CTE, including SLI’s first case, former WWE wrestler Chris Benoit.

In 2008 Nowinski and Dr. Robert Cantu, another co-founder of SLI, partnered SLI with Boston University School of Medicine to create the Center for the Study of Traumatic Encephalopathy (BU CSTE), the world’s first research center dedicated to studying CTE. In 2009, BU Professor Ann McKee, MD, a neuropathologist and one of the world’s foremost neurodegenerative disease experts, published the seminal paper on all known cases of CTE ever identified in the medical literature, adding three new cases from the BU CSTE to bring the total to 52.

Today, SLI and BU have created the world’s largest CTE repository, with over 100 diagnosed cases and over 170 brains of former athletes and military veterans. The brain bank contains more cases of CTE than the rest of the world, combined, throughout history, and the discoveries have redefined what we know about the disease.

Learn more about the most recent CTE findings, which were discussed at the first conference dedicated exclusively to CTE, here.